unique and unique_copy

swap_ranges

template <class ForIter1, class ForIter2>    ForIter2 swap_ranges(ForIter1 start1, ForIter1 end1,                         ForIter2 start2);

The swap_ranges( ) algorithm exchanges elements in the range specified by start1 and end1 with elements in the sequence beginning at start2. It returns an iterator to the end of the sequence specified by start2.